GDP, Disposable Income, and Taxation

From economic theory,

            Disposal Income = GDP – Taxation

Equivalently,

            GDP = Disposal Income + Taxation

Does this equality hold empirically? Let’s look at US data in 2000, 2010, and 2020.

From the above table, in all years, GDP is greater than the sum of disposable income and taxation. Why does this occur?

The measurements of economic data are usually not very accurate. However, here the differences are very substantial. GDP is always greater. This suggests a systematic bias in measurement. What causes this bias?

I also have a question about the theory itself. All taxations go to support some people. Tax dollars goes to the salaries of public employees,  and contractors and benefits. At aggregate level, taxation shouldn’t reduce disposable income. In other words,

            Disposal income per capita = GDP per capita

What’s wrong with my reasoning?